QOS from Central side to Remote end

[jonesl1]

I am wanting to apply QOS onto some of our WAN circuits.   Here is my scenario.   Headquarters end has a 45Mb DS3 to the MPLS cloud.  Remote end has a multilink T1 (3Mb) connection to the MPLS cloud.   We are doing BGP to the cloud itself.     My problem is, the remote links request data from the Headquarters end (which works fine going from remote to HQ).  However, when the download/file transfer starts, it completely saturates the 3Mb connection and nobody else can do anything on that circuit.   I have applied some policing on the HQ end, but I also have a few hundred remote sites connecting to this cloud with the same AS number which causes some issues.   Does anyone know of a way to QOS or prioritize mission critical traffic in this manner? 

Please any help with this matter would be appreciated.

Thanks,

[Joseph W. Doherty]

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Posting

Normally, there are two things that normally can be done; BTW they are not mutually exclusive.

If your device supports CBWFQ, you could define a class per branch and shape for the branch's egress bandwidth.  However, if you have several hundred branches, you may run out of policy classes.

The other approach is to use vendor QoS.  Many MPLS vendors will offer some kind of QoS support although sometimes it's an extra cost option.

[jonesl1]

Thank you for replying Joseph.

I read somewhere that if the link is anywhere between 1.5Mb and 45Mb, then you should only have a maximum of 5 classes.   Is this a true statement?   Also, how many classes can you have?

[Joseph W. Doherty · Accepted solution]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

I don't recall seeing a recommendation to have only up to 5 classes, as even the (later) RFC recommendation has twelve (?) classes; although that's for classes to the same destination.  I wouldn't consider this the same as for branch classification.

How many classes depends on the platform and IOS version, but I think I recall values of around 255 classes in later versions.

[jonesl1]

Thank you for your response and help.  It's much appreciated.